add logging for errors (#239)

diff --git a/provider/consumer.py b/provider/consumer.py
index 2a0c65a..4728d27 100644
--- a/provider/consumer.py
+++ b/provider/consumer.py
@@ -481,6 +481,7 @@
         return key
 
     def __error_callback(self, error):
+        logging.warning(error)
         if not self.connected and error.code() == KafkaError._AUTHENTICATION:
             self.authErrors = self.authErrors + 1
             if self.authErrors > self.maxAuthErrors: